Vibrator starter for pulse jet engines



Jan. 5, 1960 .1. A. MELENRIC VIBRATOR STARTER FOR PULSE JET ENGINES Filed July 13. 1953 COIL INVENTOR. JouN A. Muamzlc,

ATTORNEY United States Patent 1 2,919,547 VIBRATOR STARTER FOR PULSE JET ENGINES John A. Melenric, Wichita, Kans. Application July 13, 1953, Serial No. 367,525 3 Claims. (Cl. 60-3914) This invention relates in general to engine starters and in particular to a vibrating type of starter for a pulse jet engine in which flap pulsating valves are employed.

As a general rule, pulse jet engines are rather difiicult to start and this difiiculty increases as the size of the engine decreases, because of the high frequency of vibration of the flap valves in the smaller engines.

It has been found that if a vibrating device can be mechanically affixed to the pulse jet engine and made to pulsate in resonance within the range of pulse frequency of the flap valves the valves themselves will begin to pulsate. Then, with the addition of the fuel and air and an ignition means, the engine will be started and will run of its own accord.

It is therefore one object of my invention to provide a pulse jet engine starting device comprising a vibrator securable to the frame of the jet engine, a spark generating means and means for setting the frequency of vibrations and spark to the pulse jet frequency.

It is another object of my invention to provide a starting device for a pulse jet engine comprising a vibrator securable to the frame of the jet engine and means for setting the frequency of the vibrator to the pulsation frequency of the jet engine so that the resonance of the vibrator will cause the flap valves of the jet engine to resonate with the vibrator to start the engine.

It is one more object of the invention to provide a starting device for a pulse jet engine comprising a vibrator securable to the frame of the jet engine, a spark generating means, and means for setting the frequency of the vibrator and the spark frequency in resonance with the frequency of vibration of the flap valves on the engme.

Other objects and advantages as well as the construction and operation of my invention will be apparent by reference to the following description in connection with the accompanying drawing in which:

Fig. 1 is a longitudinal elevational view, partly diagrammatic and partly in section, showing the vibrator mounted on the tail end of a pulse jet engine, with the electrical current source and the spark plug.

Fig. 2 is a diagrammatic view of the vibrator and spark generating circuit.

Fig. 3 is a longitudinal elevational view of a pulse jet engine with my vibrator starter attached with portions being shown in section.

Referring now to the drawing by numerals of reference, 1 indicates the tail of a pulse jet engine which has flap valves 2 of any suitable type mounted in combustion chamber 1'.

The vibrator has a ring 3 which mounts to the pulse jet engine by means of fastening member 4. A housing 5 carries induction coils 6, vibrator plate 7, contacts 8 and 9, spark coil 10 and condenser 11.

Screw means 12 permit adjustment of the spark gap between contacts 8 and 9 and consequent frequency of vibration of the vibrator. Adjustment screw 13 on the end of the vibrator plate .7, by changing the moment of inertia of the vibrator plate, also aids in changing the frequency of vibration.

A spark plug 14 is provided in the pulse jet engine and is connected by conductors 15 to the spark coil. A suitable electrical current source such as dry cells 16 or the like are provided and connected by suitable conductors to the spark plug and coils.

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In operation, with the ring 3 mounted on the tail or nose section of the pulse jet engine, and suitable connections from the vibrator unit to the spark plug and the batteries it is necessary only to supply fuel and air to the pulse jet engine, and adjust the spark gap by means of screw 12 until the flap valves begin to resonate and the engine starts.

The induction coils are mounted with their cores substantially parallel to the longitudinal axis of the tail of the pulse jet engine. The vibrations set up by plate 7 are substantially parallel to said axis. The flap valves are of a type similar to those shown in conventional pulse jet engines or in applicants copending application, Serial No. 553,456, filed December 16, 1955, said valves beginning to function when the vibrator is in resonance with the natural period of resonance of the flap valves. Upon application of fuel and an ignition means the engine will start when the flap valves are vibrated.

When the engine is functioning properly the vibrator may be removed and the engine is ready for flight.

From the foregoing it will be seen that I have devised a simple and effective starter for pulse jet engines which can be easily and quickly mounted or removed from the pulse jet engine and which can be quickly and easily adjusted to the natural resonance frequency of the flap valves of the pulse jet to cause the flap valves therein to pulsate.

It is obvious that changes in form, proportion and details of construction may be resorted to without departing from the spirit of my invention and I reserve all rights to such changes as come within the scope of these specifications and the claims which follow.

What I claim as new and desire to secure by Letters Patent is:

1. A starter for pulse jet engines having flap valves, a housing removably mountable on one end of the pulse jet engine, a vibrator in the housing adapted to impart vibrations to the engine and thereby to the valves in the pulse jet engine, a spark plug in the engine and means synchronized with the vibrator producing an ignition spark in the spark plug in the engine in synchronization with the vibrations generated by the vibrator.

2. A starter for pulse jet engines employing flap valves and a tail pipe, a vibrator, a housing for the vibrator, a ring mounting on the housing adapted to be removably received on one end of the engine, means for synchronizing the vibrator and the flap valves to make the vibrator resonate with the flap valves, a spark plug in the engine, and means including a current source for producing an ignition spark in the spark plug in the engine in synchronization with the operation of the flap valves.

3. A starter for pulse jet engines having flap valves and a tail pipe and inlet pipe, a housing removably mounted on the tail pipe or inlet pipe, a vibrator in the housing adapted to impart vibrations to the tail pipe or inlet pipe and thereby to the valves in the pulse jet engine, a spark plug in the engine, and means including a current source producing an ignition spark at the spark plug in the engine in synchronization with the vibrations generated by the vibrator.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Dec. 1, 19 33 

